diff --git a/.github/workflows/sbt.yml b/.github/workflows/sbt.yml
index b7324597..7324cc23 100644
--- a/.github/workflows/sbt.yml
+++ b/.github/workflows/sbt.yml
@@ -21,7 +21,7 @@ jobs:
       run: sbt test
 
   deps:
-    # if: github.head_ref == 'master'
+    if: github.ref == 'refs/heads/master'
 
     runs-on: ubuntu-latest
 
diff --git a/src/main/scala/eu/sim642/adventofcode2019/Day18.scala b/src/main/scala/eu/sim642/adventofcode2019/Day18.scala
index 67855209..b083cccc 100644
--- a/src/main/scala/eu/sim642/adventofcode2019/Day18.scala
+++ b/src/main/scala/eu/sim642/adventofcode2019/Day18.scala
@@ -23,6 +23,7 @@ object Day18 {
   trait KeyNeighborsSolution extends Solution {
     case class PathData(distance: Int, pathDoors: Set[Pos], pathKeys: Set[Pos])
 
+    // https://en.wikipedia.org/wiki/Transit_node_routing
     def getKeyNeighbors(input: Input): collection.Map[Pos, collection.Map[Pos, PathData]]
 
     override def collectKeysSteps(input: Input): Int = {
diff --git a/src/main/scala/eu/sim642/adventofcode2021/Day23.scala b/src/main/scala/eu/sim642/adventofcode2021/Day23.scala
index 78440534..569869ad 100644
--- a/src/main/scala/eu/sim642/adventofcode2021/Day23.scala
+++ b/src/main/scala/eu/sim642/adventofcode2021/Day23.scala
@@ -33,6 +33,7 @@ object Day23 {
 
     private case class PathData(length: Int, pathPoss: Set[Pos])
 
+    // https://en.wikipedia.org/wiki/Transit_node_routing
     private val posNeighbors: collection.Map[Pos, collection.Map[Pos, PathData]] = {
       val allPoss: Set[Pos] = hallways ++ room2amphipod.keySet
 
diff --git a/src/main/scala/eu/sim642/adventofcode2022/Day16.scala b/src/main/scala/eu/sim642/adventofcode2022/Day16.scala
index 5621fecc..0f08baea 100644
--- a/src/main/scala/eu/sim642/adventofcode2022/Day16.scala
+++ b/src/main/scala/eu/sim642/adventofcode2022/Day16.scala
@@ -12,6 +12,7 @@ object Day16 {
 
   case class ValveData(flowRate: Int, tunnels: Seq[Valve])
 
+  // https://en.wikipedia.org/wiki/Transit_node_routing
   def valveDists(valves: Map[Valve, ValveData]): collection.Map[Valve, collection.Map[Valve, Int]] = {
     val dists: mutable.Map[Valve, mutable.Map[Valve, Int]] = valves.view.mapValues(_.tunnels.map(_ -> 1).to(mutable.Map)).to(mutable.Map)
     // Floyd-Warshall
diff --git a/src/main/scala/eu/sim642/adventofcode2024/Day25.scala b/src/main/scala/eu/sim642/adventofcode2024/Day25.scala
index c74ccb1a..6607a194 100644
--- a/src/main/scala/eu/sim642/adventofcode2024/Day25.scala
+++ b/src/main/scala/eu/sim642/adventofcode2024/Day25.scala
@@ -13,11 +13,7 @@ object Day25 {
 
   def countLockKeyFits(lockKeys: Seq[Grid[Boolean]]): Int = {
     val (keys, locks) = lockKeys.partition(isKey)
-    (for {
-      key <- keys
-      lock <- locks
-      if fits(key, lock)
-    } yield ()).size
+    keys.view.map(key => locks.count(fits(key, _))).sum
   }
 
   def parseLockKey(s: String): Grid[Boolean] = s.linesIterator.map(_.map(_ == '#').toVector).toVector